Comparing Emission Mitigation Effort

A natural outcome of the emerging pledge and review approach to international climate change policy is interest in comparing mitigation effort among countries. Domestic publics and stakeholders will have an interest in knowing if peer countries are undertaking (or planning to undertake) comparable effort in mitigating their greenhouse gas emissions. Moreover, if considered inadequate to address the risks posed by climate change, the aggregate effort will likely prompt broader interest in identifying those countries where greater effort is arguably warranted on the basis of peer comparisons. Both assessments require metrics of effort and comparisons among countries. We propose a framework for such an exercise, drawing from a set of principles for designing and implementing informative metrics. We present a template for organizing metrics on mitigation effort, for both ex-ante and ex-post review. We also provide preliminary assessments of effort along emissions, price, and cost metrics for post–2020 climate policy contributions by China, the European Union, Russia, and the United States. We close with a discussion of the role of academics and civil society in promoting transparency and facilitating the evaluation and comparison of effort